If you’re a Netflix customer who’s paying an extra $1 a month to rent movies on Blu-ray, you might have noticed that the discs aren’t being delivered as quickly as DVDs.

Josh Lowensohn, from CNET News, was complaining that he’s had Futurama: Bender’s Game, in his queue for over a month. The flick Wall-E has been in the queue since November 18. Why is it taking so long for Netflix to ship?

I called Steve Swasey, Netflix’s very accessible spokesman, and he said the Web video store simply doesn’t have enough Blu-ray discs to go around, especially when it comes to hot new releases.

Hollywood just isn’t providing enough Blu-ray copies of newly released films as the company would like to get, according to Swasey. That’s the first bottleneck. But the spokesman said the problem isn’t all the fault of the studios. Once larger numbers of Blu-ray discs for a film are available, the company won’t necessarily buy them.

“There is an expense to that,” Swasey said. “These things cost money. We deploy money where we think it’s going to be most efficient to keep subscribers and investors happy. It’s always check and balances.”

Here’s the final problem that affects frequent users of Netflix and this won’t come as a surprise. If a movie is hot and the company doesn’t have enough to go around, the film is going to the user that rents fewer new releases, according to Swasey.

“What we’re doing is giving new releases to the person who hasn’t rented as much,” he said. “We’ve been doing this for a couple of years and fully disclose this in our terms of agreement. If we have a shortage of titles we do what we think is equitable and give the title to the person who hasn’t rented as much or who hasn’t gotten as much enjoyment from the service.”

Lowensohn is among the unlucky Netflix users who rents a lot of new releases. He says he rents about 20 movies a month. When I tell him what Swasey’s response is, he is less than satisfied.

“Sucks,” Lowensohn said. “Why are they charging me more? I’m paying but I’m not receiving the movies I want.”

Swasey said Netflix is bullish on Blu-ray, but right now only a small percentage of customers are asking for the discs. So far, Netflix’s Blu-ray service has about 500,000 subscribers. Netflix’s traditional DVD business has 8.7 million subscribers.